Treatment of leather



Patented Oct. 11, 1938 UNITED STATES PATENT OFFICE.

TREATMENT OF LEATHER Charles H. Campbell, Kent, Ohio No Drawing. Application April 16, 1937, Serial No. 137,387

, 4 Claims.

10 or stuffed for the above purposes with animal,

mineral or vegetable oils to which have been added various fats and waxes, etc. These have not been entirely satisfactory, 'in that by the use of these oils, leather is not thoroughly impreg- 15 nated, whereby the fibres thereof will be effectively lubricated and the various fats, waxes, etc. are not evenly distributed throughout the body of the leather because these oils are not true solvents ofall the added ingredients and the various added materials are prevented from impregnating the leather due to the leather fibres acting as a filter and any and all added materials not in true solution, by this filtering action, deposit at or near the surface of the leather. Prior 25 leathers are edged with difficulty in finishing edgers, such as used, for example, in the manufacture of shoes and-are also subject to attack by bacterial action or fungus growth.

The general purpose of the present invention 30 is to provide a base oil for use in treatment of leather either alone or with the addition of other animal, vegetable or mineral oils, gums, waxes, resins, rosins, greases and other fatty products, whereby leather is secured with a high degree of flexibility, a finished product plump and hard enough to edge easily and which is preserved against deterioration by bacterial or fungus growth on the surface when in storage and before sale.

- 40 In selecting a base oil it is necessary to select an oil which has a high fire and fiash point so as to minimize the fire hazard. In the tanneries,

the leather is, dried in dry alleys almost always constructed of wood which are oil soaked from 45 constant usage, so that a high fire and flash point becomes absolutely necessary.

In accordance with the present invention, a

base oil is selected which comprises distillation products of coal, which distillat a range from 50 200 C. to 270 to 280 C. This oil is obtained after the so called light oils, including benzol,

toluol, xylol, and the naphthas have been distilled over. It is a naphthalene base oil and is a combination of the higher boiling homologues of the 6Q heavy naphthas.

This oil preferably should not carry over 8 to 10 percent. naphthalene and since the oil originally running from the stills carries from 25 to 40 percent naphthalene, depending uponthe type of coal used, time of coking, and other variables in the stilling process, it is necessary to reduce the percentage of naphthalene, which may be accomplished by treating the distilled products at low temperatures for given periods of time. Prior to this treatment or-subsequent thereto, the oil preferably is treated to eliminate objectionable odor in the finished-leather, as by blowing superheated steam through the oil to remove traces of gas that may be present.

These oils, as they distill over, also carry free carbon and other ingredients which render the oil comparatively dark in color, so that it could not be effectively used in light colored finished leathers. To obviate this, difilculty, the oil is preferably subjected to a centrifuging or filtering process to remove these foreign ingredients. I This base oil has a high fire and flash point whereby it is safe for use in the treatment of leather and possesses certain desirable solvent penetrating and antiseptic properties. It may be used alone, of course, but in most cases it is used in percentages as low as 20 to 40 percent, along with a-variety of gums, waxes, resins, rosins, vegetable or animal oils, greasy or fatty products of various types, many of'which have heretofore been used with more or less beneficial results in leathers. The improved oil, however, possesses the property of readily penetrating into the leather, but since the foregoing materials may be readily mixed with or. dissolved in the improved base oil,.it acts as an effective vehicle to carry the other materials into the fibre of the leather so as to thoroughly impregnate the same. It makes the finished leather flexible, hard and plump, easy to edge and makes it damp-proof, and preserves it against bacterial growths. It has antiseptic qualities due to the naphthalene present therein.

The improved base oil distills between 200 C. and 270 and 280 C. and is a naphthalene base oil comprising the higher boiling point homologues of the heavy naphthas. The fire and flash of this oil is approximately 196 F.

Modifications of the inventionmay be resorted to without departing from the spirit thereof or the scope of the appended claims.

What is claimed is:

1. A process for the treatment of leather, which comprises impregnating the leather with a base oil which essentially consists of a distillation of 56 011 from coal products at temperatures ranging irom 200 C. to 280 C., carrying less than ten percent naphthalene and treated to remove gases and eliminate odor and remove solid particles to eliminate color.

2. That process for the treatment of leather, which comprises impregnating the leather with a base oil which consists essentially of the higher boiling point homologues of the heavy naphthas, said '01] being produced from the distillation of coal.

3. The process as set forth in claim 1 in which that class of leather-treating substances including gums, waxes, resins,-rosins; vegetable or animal or mineral oils, greasy or fatty products are added to the base oil prior to impregnating the leather.

4. That process for the treatment of leather which comprises impregnating the leather with a base oil which consists essentially of the higher boiling point homologues of the heavy naphthas produced from the distillation of coal in which that class of leather-treating substances including gums, waxes, resins, rosins, vegetable or animal or mineral oils, greasy-or fatty products are added to the base oil prior to impregnating the leather.

' CHARLES H. CAMPBELL. 

